Emulsifiers, especially based on polyisobutylenamines

ABSTRACT

Compounds, in particular those based on polyisobutyleneamines, are suitable as emulsifiers for water-in-oil emulsions and are used in particular as additives for fuels and lubricants.  
     The novel compounds are those of the formula I  
                 
 
     where R 1  is unsubstituted or C 1 -C 12 -alkyl-substituted C 1 -C 8 -alkylene or C 2 -C 8 -alkenylene,  
     R 2  is linear or branched C 8 -C 350 -alkyl or C 8 -C 350 -alkenyl,  
     R 3  and R 4 , independently of one another, are each H, methyl or ethyl and together have not more than 2 carbon atoms,  
     R 5  is H, M + , SO 3 H, SO 3   − M + , OPO 3 H, OPO 3   − M +  or C(O)R 7 ,  
     M +  is NH 4   + , an alkali metal ion or 0.5 alkaline earth metal ion,  
     R 7  is a linear C 2 - to C 10 -hydrocarbon radical substituted by at least one hydrophilic group and  
     y and z, independently of one another, are each an integer from 0 to 50, and R 5  is H if y is 0, and R 6  is H if z is 0.

[0001] The present invention relates to compounds, in particular based on polyisobutyleneamines, which are suitable as emulsifiers for water-in-oil emulsions, processes for the preparation of such compounds and the emulsions themselves.

[0002] The present invention also relates to the use of such compounds as additives for fuels and lubricants and as corrosion-inhibiting additives in aqueous liquids, and fuels, lubricants, fuel additive concentrates and lubricant additive concentrates and aqueous liquids containing the novel compounds.

[0003] Compounds of various types having emulsifying properties are disclosed in the prior art. Inter alia, derivatives of polyisobutenyl-substituted succinic anhydride are used in various applications.

[0004] For example, U.S. Pat. No. 4,225,447 describes water-in-oil emulsions which are used as lubricants and contain a polyisobutenyl-substituted succinic anhydride, an alkali (alkaline earth) metal salt of a polyisobutenyl-substituted succinic acid or a polyisobutenylsubstituted succinamide as an emulsifier.

[0005] GB-A 2,157,744 discloses drilling fluids which contain both an emulsifier, i.e. graft or block copolymers of polycarboxylic acids and polyethylene glycol, and surfactants. The surfactants used are compounds which are prepared from a polyisobutenyl-substituted succinic anhydride and polyols, polyamines, hydroxycarboxylic acids or amino alcohols.

[0006] EP-A 0 156 572 describes the use of anionic surface-active substances based on polyisobutenyl-substituted succinic acid derivatives for the preparation of water-in-oil or oil-in-water emulsions.

[0007] BASF AG's German Application filed on Jan. 25, 2000 and having the application number 100 03 105.6 describes the use of alkoxylated polyisobutylenes as emulsifiers in water-in-fuel emulsions. These alkoxylated polyisobutylenes can be described by the formula R—(CH₂)_(n)—(O-A)_(m)—OH. Here, R is a polyisobutylene having a weight average molar mass of from 300 to 2300, preferably from 500 to 2000. A is an alkylene radical of 2 to 8 carbon atoms. m is a number from 1 to 200 which is chosen so that the alkoxylated polyisobutylene contains from 0.2 to 1.5 alkylene oxide units, preferably 0.5 alkylene oxide unit, per C₄ unit; n is either 0 or 1.

[0008] BASF AG's German Application filed on Jul. 28, 2000 and having the application number 100 36 956.1 describes, inter alia, the use of amides of the formula R1R²NR³ as emulsifiers in water-in-oil emulsions, where R³ is an acyl radical of a mono- or polycarboxylic acid, R¹ is derived, inter alia, from a poly-1-butylene, poly-2-butylene or isobutylene or a mixture thereof and R² may be a polyalkylenepolyamine or a polyalkyleneimine radical.

[0009] In addition to emulsifiers, friction-reducing additives for fuels and lubricants are also disclosed in the prior art.

[0010] Thus, U.S. Pat. No. 5,858,029 describes friction-reducing additives for fuels and lubricants, in particular compounds of the formula R¹(—O(R²)—)_(a)NH(CO)—R³—OH, where R¹ is C₁- to C₆₀-alkyl, R² is C₁- to C₄-alkylene, a is an integer from 1 to 12 and R³ is C₁- to C₄-alkylene or substituted alkylene or cycloalkylene, being used as friction-reducing additives. In addition, polyisobutenyl-substituted succinimides may be present as dispersants and polyalkyleneamines, such as polyisobutyleneamines, may be present as surfactants.

[0011] The abovementioned compounds disclosed in the prior art have various disadvantages with regard to preparation and/or product properties. In the case of some compounds, the synthesis gives rise to different yields of byproducts which—unless they are removed—can make it more difficult to establish a constant viscosity of the emulsifier. Disadvantages can also occur in the preparation of emulsions: frequently, the emulsions have insufficeint stability so that phase separation occurs during storage. The emulsifiers used must therefore be employed in high concentrations in order to permit the formation of a stable emulsion.

[0012] There is therefore a need for compounds which can be used as emulsifiers and do not have said disadvantages. Particularly in the area of water-in-fuel emulsions, emulsifiers which produce relatively stable emulsions and additionally permit fuel combustion which is as complete as possible and substantially residue-free are required.

[0013] It is an object of the present invention to provide further compounds which can be used as emulsifiers in oil-in-water and water-in-oil emulsions.

[0014] We have found that this object is achieved by compounds of the formula I,

[0015] where R¹ is unsubstituted or C₁-C₁₋₂-alkyl-substituted C₁-C₈-alkylene or C₂-C₈-alkenylene,

[0016] R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₅₀-alkenyl,

[0017] R³ and R⁴, independently of one another, are each H, methyl or ethyl, and R³ and R⁴ together have not more than 2 carbon atoms,

[0018] R⁵ and R⁶, independently of one another, are each H, M⁺, SO₃H, SO₃ ⁻M⁺, OPO₃H, OPO₃ ⁻M⁺ or C(O)R⁷,

[0019] M⁺ is NH₄ ⁺, an alkali metal ion or 0.5 alkaline earth metal ion,

[0020] R⁷ is a linear C₂-C₁₀-hydrocarbon radical substituted by at least one hydrophilic group and

[0021] y and z, independently of one another, are each an integer from 0 to 50 and

[0022] R⁵ is H if y is 0, and R⁶ is H if z is 0.

[0023] The novel compounds (I) can be used as emulsifiers in water-in-oil emulsions. The fact that frequently lower concentrations than with the use of conventional emulsifiers are required for producing stable emulsions is an advantage. If the novel compounds are used in oil-in-water emulsions, stable vesicles can be produced under the action of ultrasound.

[0024] The novel compounds can also be used in a variety of ways, for example as additives in fuels and lubricants, as corrosion-inhibiting additives in aqueous liquids and as dispersants for pigments, such as TiO₂.

[0025] The present invention also relates to processes for the preparation of the compounds (I). These processes are shown schematically in FIG. 1.

[0026]FIG. 1: Processes for the preparation of compounds (I) where R⁵=R⁶=H.

[0027] Suitable reaction conditions for the amidation of the dicarboxylic acids HO₂C—R¹—CO₂H with the amines R²—NH₂ (FIG. 1, Reaction step a1) to give bisamides (II) are known to a person skilled in the art or can be determined by a few preliminary experiments.

[0028] The dicarboxylic acids and amines can be reacted with one another both in organic solvents and in the absence of a solvent. Suitable organic solvents are, for example, Solvesso® 150 from Shell and isododecane.

[0029] In a preferred embodiment of the process, the reaction is carried out under reduced pressure, for example at from 5 to 50 mbar, and the resulting water is distilled off continuously during the reaction. Purification of the resulting bisamides (II)—before further reaction—is generally unnecessary.

[0030] The bisamide (II) thus obtainable is then reacted with alkylene oxides (III) by a process known to a person skilled in the art to give alcohols of the formula I in which R⁵ and R⁶ are each H (FIG. 1, Reaction step a2). This reaction is carried out in general in the presence of a conventional basic catalyst, such as KOH, NaOH, NaOMe, KtBuO, Ca(OH)₂ or CaO, or a support catalyst, such as a zeolite.

[0031] Hydrophilic groups can be introduced into the novel compounds (I) thus obtainable, in which R⁵ and R⁶ are each H. For example, the novel compounds (I) in which R⁵ and R⁶ are each H can be sulfated with SO₃ to give sulfuric esters ((I) where R⁵=R⁶=SO₃H) reacted with P₄O₁₀ to give phosphoric esters ((I) where R⁵=R⁶=OPO₃H) or reacted with compounds HO₂C—R⁷ to give esters ((I) where R⁵=R⁶=C(O)R⁷), said reactions being carried out by standard processes as described, for example, in Falbe (Editor), Surfactants in consumer products 1986, Springer Verlag Berlin, page 54 et seq., in the US Application with the application number 60 160 212 of Oct. 19, 1999 and in the PCT Application with the application number PCT/EP/00/09923.

[0032] By adding NH₃ or suitable alkali (alkaline earth) metal salts, such as alkali (alkaline earth) metal hydroxides, the corresponding sulfates (I) where R⁵=R⁶=SO₃ ⁻M⁺, or phosphates (I) where R⁵=R⁶=OPO₃M⁺, where M⁺ is NH₄ ⁺, an alkali metal ion or 0.5 alkaline earth metal ion, can be prepared from the sulfuric esters and phosphoric esters, respectively.

[0033] Alternatively (FIG. 1, Reaction steps b1, b2 and b3), compounds (I) in which R⁵ and R⁶ are each H can be prepared by first reacting amines R²—NH₂ with alkylene oxides (III) to give alcohols of the formula IV. Dicarboxylic acids HO₂C—R¹—CO₂H are then reacted with the alcohols (IV), in general under the same reaction conditions which are applied to the reaction of the dicarboxylic acids HO₂C—R¹—CO₂H with the amines R²—NH₂. The resulting bisamides of the formula V where R⁵=R⁶=H can be reacted with alkylene oxides III to give compounds (I) in which R⁵ and R⁶ are each H. Hydrophilic groups can be introduced into the bisamides of the formula V where R⁵=R⁶=H also directly, as described in the preceding section.

[0034] Dicarboxylic acids HO₂C—R¹—CO₂H in which R¹ is C₁-C₈-alkylene or C₂-C₈-alkenylene and is unsubstituted or substituted by C₁-C₁₂-alkyl are used. In the present invention, the term alkenylene also includes polyunsaturated bivalent hydrocarbon radicals R¹.

[0035] Suitable dicarboxylic acids are, for example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, which may carry C₁-C₁₂-alkyl groups in any desired position. The use of unsubstituted dicarboxylic acids is preferred. Among these, succinic acid, glutaric acid, adipic acid, pimelic acid or suberic acid is preferably used, particularly preferably succinic acid, glutaric acid or adipic acid.

[0036] In general, amines R²—NH₂ in which R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₅₀-alkenyl are suitable for the preparation of compounds (1) in which R⁵ and R⁶ are each H. Here, alkenyl also includes polyunsaturated hydrocarbon radicals R².

[0037] Amines R²—NH₂ in which R² is C₂₂-C₃₅₀-polyisobutenyl are preferably used.

[0038] Polyisobutyleneamines R²—NH₂ where R² is C₂₂-C₃₅₀-polyisobutenyl are prepared from the corresponding polyisobutylenes by standard processes, as described, for example, in DE-A 196 20 262, EP-A 0 244 616 and WO-A 97/03946. The amount of amino groups can be determined by titration with HCl and then converted into mg KOH per g of substance. The amount of amino groups per unit weight of substance is then the amine number. In general, polyisobutylenes which have a number average molecular weight from 300 to 5000, preferably from 500 to 2300, particularly preferably from 500 to 1000, are used for the preparation of the polyisobutyleneamines.

[0039] Among the polyisobutylenes having a number average molecular weight within said ranges, those which have a high content of vinylidene groups are preferably used. In the context of the present invention, this is understood as meaning an amount of ≧70, preferably ≧80, particularly preferably ≧85, mol % of vinylidene groups.

[0040] Those polyisobutylenes which have a number average molecular weight within the abovementioned ranges, a high content of vinylidene groups and a uniform polymer skeleton structure are particularly preferably used. Examples of polyisobutylenes having a uniform polymer skeleton structure are those polyisobutylenes which are composed of at least 85, preferably at least 90, particularly preferably at least 95, % by weight of isobutylene units.

[0041] Polyisobutylenes having a number average molecular weight within said ranges, a high content of vinylidene groups and a uniform skeleton structure may furthermore have a polydispersity of ≦2.5, preferably ≦2.0. Polydispersity is understood as meaning the quotient M_(w)/M_(n) of weight average molecular weight M_(w) and number average molecular weight M_(n). The polydispersity is a measure of the molecular weight distribution of a polymer.

[0042] Polyisobutylenes which have a number average molecular weight within said ranges, are composed substantially of isobutylene units and have a high content of vinylidene groups are obtainable, for example, under the trade name Glissopal® from BASF AG, such as Glissopal® 1000 having an M_(n) of 1000, Glissopal® V 33 having an M_(n) of 550 and Glissopal® 2300 having an M_(n) of 2300.

[0043] Examples of commercially available polyisobutyleneamines are the compounds obtainable under the trade name Kerocom® PIBA from BASF AG.

[0044] Examples of suitable alkylene oxides (III) are ethylene oxide, propylene oxide, 1-butylene oxide and 2-butylene oxide. Ethylene oxide and propylene oxide are preferably used.

[0045] Compounds in which R⁷ is a linear C₂-C₁₀-hydrocarbon radical substituted by at least one hydrophilic group are used for R⁷—CO₂H. The term C₂-C₁₀-hydrocarbon radical includes C₂-C₁₀-aLkyl, C₂-C₁₀-alkenyl and C₇-C₁₀-alkylaryl. The term hydrophilic groups also includes positively or negatively charged groups, and the term alkenyl includes both monounsaturated and polyunsaturated hydrocarbon radicals. Examples of hydrophilic groups are —NH₂, —NH₃ ⁺, —NR₃ ⁺ where R is C₁-C₆-alkyl, —CO₂H, —CO₂ ⁻, OPO₃H and OPO₃ ⁻. Compounds where R⁷ corresponds to the formula VI where n=1 to 4 are preferably used for R⁷—CO₂H. R⁷—CO₂H corresponds, for example, to amino acids having at least one additional carboxyl group in the molecule. The use of aspartic acid (n=1) and glutamic acid (n=2) is particularly preferred.

[0046] In addition to L-amino acids, it is also possible to use the corresponding D-amino acids or mixtures, such as the racemates of the D- and L-amino acids.

[0047] The novel compounds (I) can be used as emulsifiers in the preparation of water-in-oil emulsions. The present invention also relates to its use. It may be necessary to purify these compounds and their intermediates, for example when these compounds are used as emulsifiers for water-in-oil emulsions in the cosmetics or pharmaceutical sector.

[0048] The novel water-in-oil emulsions contain in general from 95 to 60% by weight of oil, from 3 to 35% by weight of water and from 0.2 to 10% by weight of a novel compound of the formula I.

[0049] For water-in-oil emulsions in which the oil phase is formed by a vegetable, animal or synthetic oil or fat, novel compounds of the formula I are used. Compounds of the formula I in which R⁵ and R⁶ are each H are preferably used. Such water-in-oil emlusions are used, for example, in the cosmetics or pharmaceutical sector.

[0050] Examples of vegetable, animal or synthetic oils or fats are triglycerides and glycol esters (esters of glycolic acid) of lauric acid, myristic acid, stearic acid, palmitic acid, oleic acid, linoleic acid and linolenic acid.

[0051] Compounds of the formula I are also used in water-in-oil emulsions in which the oil phase is formed by a fuel or a light or heavy heating oil. Compounds of the formula I in which R⁵ and R⁶ are not H are preferably used, and compounds of the formula I in which R⁵ and R⁶ are each SO₃H, SO₃ ⁻M⁺ or C(O)R⁷ are particularly preferably used. All conventional fuels may be used, for example diesel fuels, gasoline fuel and kerosene. Diesel fuel is preferably used.

[0052] Novel water-in-fuel emulsions may also contain one or more C₁-C₄-alcohols and/or monoethylene glycol, in particular monoethylene glycol. The amount of C₁-C₄-alcohol and/or monoethylene glycol used is from 5 to 50% by weight, based on the amount of water. By adding one or more C₁-C₄-alcohols and/or monoethylene glycol, for example, the temperature range in which the emulsion is stable can be broadened.

[0053] The novel water-in-fuel emulsions have high stability and good efficiency during combustion. It is also possible to obtain good exhaust gas values, the emission of soot and NO_(x) being significantly reduced, in particular in diesel engines. Substantially complete and residue-free combustion without deposits on the components of the combustion apparatus, for example injection nozzles, pistons, annular grooves, valves and cylinder head, can be achieved.

[0054] In addition to the abovementioned constituents, the water-in-fuel emulsions according to the present invention may have further components. These are, for example, further emulsifiers, such as sodium laurylsulfate, quaternary ammonium salts, such as ammonium nitrate, alkylglycosides, lecithins, polyethylene glycol ethers and esters, sorbitan oleates, stearates and ricinoleates, C₁₃-oxo alcohol ethoxylates and alkylphenol ethoxylates, and the block copolymers of ethylene oxide and propylene oxide, such as the Pluronic® grades from BASF AG. Sorbitan monooleate, C₁₃-oxo alcohol ethoxylates and alkylphenol ethoxylates, for example octyl- and nonylphenol ethoxylates, are preferably used as further emulsifiers.

[0055] A combination of one or more of the abovementioned further emulsifiers together with the novel emulsifiers is preferably used for the novel water-in-fuel emulsions.

[0056] If these further emulsifiers are used, they are employed in amounts of from 0.5 to 5, preferably from 1 to 2.5, % by weight, based on the total composition. The amount of this further emulsifier is chosen so that the total amount of emulsifier, i.e. novel emulsifier plus further emulsifier, does not exceed the amount of from 0.2 to 10% by weight stated for the novel emulsifier alone.

[0057] For the preparation of the novel water-in-oil emulsions, the chosen novel emulsifier is mixed with the oil, the water and the further, optionally usable components and is emulsified in a manner known per se. For example, the emulsification can be effected in a rotor mixer, by means of a mixing nozzle or by means of an ultrasound probe. Particularly good results were obtained when a mixing nozzle of the type disclosed in BASF AG's German Application, application number 198 56 604 of Dec. 8, 1998, was used. Water-in-oil emulsions for the cosmetics sector can be prepared in the same way as water-in-fuel emulsions.

[0058] In addition to their surfactant and emulsifying properties, the novel compounds (I) also have a lubricity-improving and corrosion-inhibiting effect. Moreover, they improve the antiwear behavior of liquids. The novel compounds (I) are therefore used as additives for lubricants, fuels and aqueous liquids, such as radiator liquids or drilling and cutting fluids. This use likewise forms the subject of the present invention.

[0059] The novel compounds (I) can be added directly—together with other components—to the fuels and lubricants. Alternatively, the novel compounds (I) can first be mixed with other components to give fuel or lubricant additive concentrates. These novel fuel or lubricant additive concentrates can be added in undiluted form or after dilution with one or more solvents or carrier oils to the fuels or lubricants. The addition in dilute form is preferred.

[0060] The fuels, lubricants, fuel additive concentrates and lubricant additive concentrates and aqueous liquids which contain the novel compounds of the formula I likewise form subjects of the present invention and are to be explained in more detail below.

[0061] The novel fuels generally contain—in addition to conventional components—at least one novel compound of the formula I in an amount of from 10 to 5 000, preferably from 20 to 2000, ppm, based on the total amount.

[0062] Novel lubricants contain in general from 90 to 99.9, preferably from 95 to 99.5, % by weight of a liquid, semisolid or solid lubricant and from 0.1 to 10, preferably from 0.5 to 5, % by weight of a novel compound (I), based on the total amount.

[0063] Novel fuel additive concentrates and lubricant additive concentrates contain—in addition to conventional components—at least one novel compound of the formula I in amounts of from 0.1 to 80, in particular from 0.5 to 60, % by weight, based on the total weight of the concentrate.

[0064] Conventional components for fuels or fuel additive concentrates are, for example, additives having a detergent effect, as described in BASF AG's German Application, application number 100 36 956.1, of Jul. 28, 2000 (page 14 et seq.), in BASF AG's German Application, application number 100 03 105.6, of Jan. 25, 2000, and in BASF AG's PCT Application having the application number PCT/EP/01/00496. The additives stated there and further fuel additives described there and having polar groups likewise form part of the present application and are hereby incorporated by reference.

[0065] The novel fuels and fuel additive concentrates may also contain fuel additives as described, for example, in European Patent Applications EP-A 0 277 345, 0 356 725, 0 476 485, 0 484 736, 0 539 821, 0 543 225, 0 548 617, 0 561 214, 0 567 810 and 0 568 873, German Patent Applications DE-A 39 42 860, 43 09 074, 43 09 271, 43 13 088, 44 12 489, 0 44 25 834, 195 25 938, 196 06 845, 196 06 846, 196 15 404, 196 06 844, 196 16 569, 196 18 270 and 196 14 349, and WO-A 96/03479.

[0066] Further conventional components are, for example, further corrosion-inhibiting additives, antioxidants, stabilizers, antistatic agents, organometallic compounds, antiwear additives, markers and cetane number improvers, flow improvers, biocides, such as glutaraldehyde or glyoxal. The biocides are usually used in an amount of from 0.01 to 3% by weight, based on the total weight of the concentrate.

[0067] Examples of further corrosion-inhibiting additives are those based on ammonium salts of organic carboxylic acids, which salts tend to form films, or on heterocyclic aromatics for corrosion protection of nonferrous metals.

[0068] Examples of stabilizers are those based on amines, such as p-phenylenediamine, dicyclohexylamine or derivatives thereof or on phenols, such as 2,4-di-tert-butylphenol or 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid.

[0069] Examples of organometallic compounds are ferrocene or methylcyclopentadienyl-manganesetricarbonyl.

[0070] Examples of cetane number improvers are organic C₂-C₁₀-nitrates, such as 2-ethylhexyl nitrate, and inorganic cetane number improvers for the aqueous phase, such as ammonium nitrate. 2-Ethylhexyl nitrate and ammonium nitrate are preferably used. The cetane number improvers are usually used in an amount of from 0.05 to 5% by weight, based on the total weight of the concentrate.

[0071] The suitable solvents for the novel fuel and lubricant additive concentrates are aliphatic and aromatic hydrocarbons, such as solvent naphtha, isododecane, mihagol, the fuels and lubricants themselves and carrier oils.

[0072] Carrier oils, which likewise serve for diluting the fuel additive concentrates and lubricant additive concentrates, are, for example, mineral carrier oils (base oils), in particular those of the viscosity class Solvent Neutral (SN) 100 to 500, and synthetic carrier oils based on polyolefins, (poly)esters, (alkylphenol-initiated) polyethers or (aliphatic) (alkylphenolinitiated) polyetheramines, and carrier oils based on alkoxylated long-chain alcohols or phenols. Examples of particularly suitable synthetic carrier oils are those based on polyolefins, preferably those based on polyisobutylene and on poly-α-olefins, having a number average molecular weight of from 400 to 1800. Polyethylene oxides, polypropylene oxides, polybutene oxides and mixtures thereof are also suitable carrier oils. Further suitable carrier oils and carrier oil mixtures are described, for example, in DE-A 38 38 918, DE-A 38 26 608, DE-A 41 42 241, DE-A 43 09 074, U.S. Pat. No. 4,877,416 and EP-A 0 452 328.

[0073] Novel aqueous liquids contain the novel compounds (I), if required in combination with further conventional corrosion-inhibiting additives, in general in an amount of from about 11 to 10% by weight, based on the total amount.

[0074] The examples which follow illustrate the invention.

EXAMPLES Example 1 Preparation of the Compounds of the Formula I

[0075] The composition of the compounds prepared is shown in table 1. The polyisobutyleneamine used was Kerocom® PIBA from BASF AG.

[0076] Synthesis of the Comounds A1, A2, A3 and A4

[0077] 28 g of adipic acid were added to 750 g of polyisobutyleneamine (M_(n)=1000, amine number=36) and heated for 3 hours at 200° C. under reduced pressure. When water no longer distilled off, the product A1 thus obtained was cooled and filled.

[0078] A4 was prepared analogously by reacting polyisobutyleneamine (M_(n)=550, amine number=36) with adipic acid.

[0079] The reaction of polyisobutyleneamine (M=1000, amine number=36) with the homologous dicarboxylic acids succinic acid (product A3) and glutaric acid (product A2) was carried out analogously.

[0080] (where R²=Polyisobutylenyl)

[0081] Synthesis of compound B 1

[0082] 282 g (about 130 mmol) of compound Al and 3.95 g (35.2 mmol) of KtBuO were combined and volatile components were removed in a rotary evaporator at 100° C. and 3 mbar. The reaction mixture was initially taken in a 2 l metal reactor and then blanketed three times with 5 bar nitrogen each time. The reactor contents were heated to 120° C. and 114 g (2.59 mol) of ethylene oxide were then metered in over 60 minutes until a pressure of 5 bar had been reached. Stirring was continued until the pressure remained constant. After cooling and letting down the pressure in the reactor, compound B1 having a polyethylene glycol moiety of 5.2% was obtained.

[0083] Synthesis of Compounds C1, C2 and C3

[0084] Compounds B1, B2 and B3 were sulfated in a continuous process using an SO₃/air mixture having an SO₃ content of 7% by volume. The reaction was carried out at 65° C. in a vertical falling-film reactor having a length of 95 cm and an internal diameter of 5 cm. About 400 g/h of compound B1, B2 or B3 as an 80% strength by weight solution in a suitable hydrocarbon, such as isododecane, heptane or mihagol, were metered into the reactor from above. The amount of SO₃/air mixture fed to the falling-film reactor was controlled by means of the acid number of the sulfated product. The acid number is a measure of the amount of acid groups, is determined by titration with KOH and is stated in mg KOH per g of substance. The acid numbers were 22 in the case of C1, 26 in the case of C2 and 41 in the case of C3. The products were neutralized batchwise at 25° C. with 25% strength by weight aqueous NaOH solution.

[0085] Synthesis of D1

[0086] 500 g of compound B 1 were dissolved in 500 ml of mihagol, 48 g of L-glutamic acid were added and heating was carried out at from 160° C. to 180° C. for 90 minutes under reduced pressure.

[0087] Synthesis of D2

[0088] The reaction of compound B 1 with 45 g of L-aspartic acid to give product D2 was carried out analogously to the synthesis of D1. TABLE 1 Composition of the novel compounds y + z (R³, R⁴ = M_(n) of H; ethylene R⁷—CO₂H Batch R²—NH₂ R¹ oxide) (amino acid) R⁵ = R⁶ A1 1000 (CH₂)₄ — — H A2 1000 (CH₂)₃ — — H A3 1000 (CH₂)₂ — — H A4 550 (CH₂)₄ — — H B1 1000 (CH₂)₄ 15 — H B2 1000 (CH₂)₂ 10 — H B3 550 (CH₂)₄ 10 — H C1 1000 (CH₂)₄ 15 — H C2 1000 (CH₂)₂ 10 — SO³⁻M⁺ C3 550 (CH₂)₄ 10 — SO³⁻M⁺ D1 1000 (CH₂)₄ 15 L-glutamic acid C(O)R⁷ D2 1000 (CH₂)₄ 15 L-aspartic acid C(O)R⁷ D3 550 (CH₂)₄ 10 L-glutamic acid C(O)R⁷

Example 2 Water-in-Fuel Emulsions

[0089] In each case a 1% strength by weight solution of an emulsifier mixture in diesel fuel was prepared, which emulsifier mixture was composed of 6 parts of a novel compound (C1, C2, C3, D1, D2 or D3) and 2 parts of a C₁₃-oxo alcohol ethoxylate (Lutensol® TO 7 from BASF AG), and 2 parts of an alkylphenol ethoxylate (Emulan® OP 25). 500 g of this mixture were stirred with 100 ml of water for 15 minutes at a speed of 24, 000 rpm using an Ultra-Turrax® (Jahnke and Kunkel laboratory apparatus T25).

[0090] For comparison, 6 parts of sorbitan monooleate (S-MAZ 80 from BASF AG) were used instead of the novel compounds. TABLE 2 Time to Amount of beginning emulsifier in the of phase Corrosion Batch Emulsifier mixture separation protection 1 C1 1%   26 d +0 2 C2 1%   28 d +0 3 C3 1%   30 d +0 4 D1 1% >30 d ++ 5 D2 1% >30 d ++ 6 D3 1%   29 d ++ Comp. 1 S-MAZ 80 1%    6 h −0 Comp. 2 S-MAZ 80 2%   19 d −0

[0091] The results in table 2 show that the water-in-fuel emulsions of the novel compounds show scarcely any signs of phase separation after storage for 30 days, whereas phase separation was observed in the comparative example after only 6 hours. Even when the concentration of emulsifier was increased from 1 to 2%, based on the diesel fuel, phase separation was observed after 19 days (comparative example 2).

Example 3 Use of the Novel Compounds as Corrosion-Inhibiting Additives

[0092] A 20×40 mm iron sheet is blasted with 40 μm glass beads and then—analogously to ASTM D-665—immersed in the emulsions prepared under Example 1 and stored for 24 hours at 40±1° C. After 24 hours, the iron sheet is investigated for rust formation. Here, the meanings are as follows: ++ no rust formation; +0 slight rust deposit; −0 rust formation on more than 25% of the area of the test sheet; — rust formation on more than 50% of the test sheet.

[0093] As the results in table 2 show, only slight rust deposition was observed for the use of the novel compounds as corrosion-inhibiting additives. In contrast, rust formation occurred on more than 25% of the area of the test sheet with use of sorbitan monooleate (comparative examples 1 and 2).

Example 4 Use of the Novel Compounds in Fuels and their Antiwear Behavior

[0094] The novel compounds B3, C1, D1 and D2 were each dissolved individually in an additivefree diesel fuel (Miro, Karlsruhe). The concentration of additive in the diesel fuel was 75 ppm. The assessment of the antiwear behavior was carried out by the HFRR test (high frequency roller rig test), which was carried out according to ISO 12156-1. The length of the resulting furrows was measured and was used as a measure for the wear. The shorter the furrows, the better was the wear protection of the additive introduced. TABLE 3 Additive Length of the furrows [μm] No additives 595 Compound B3 440 Compound C1 370 Compound D1 365 Compound D2 390 C₁₆- to C₂₂-carboxylic acid mixture (PC30 ® from 420 Elf)

[0095] For comparison, the furrow formation with the use of additive-free diesel fuel and with the use of diesel fuel to which C₁₆- to C₂₂-carboxylic acid mixture has been added was observed. 

We claim:
 1. A compound of the formula I

where R¹ is unsubstituted or C₁-C₁₂-alkyl-substituted C₁-C₈-alkylene or C₂-C₈-alkenylene, preferably unsubstituted C₂-C₄-alkylene, R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₋₅₀-alkenyl, preferably C₂₂-C₃₅₀-polyisobutenyl, R³ and R⁴, independently of one another, are each H, methyl or ethyl and together have not more than 2 carbon atoms, R⁵ and R⁶, independently of one another, are each H, M⁺, SO₃H, SO₃ ⁻M⁺, OPO₃H, OPO₃ ⁻M⁺ or C(O)R⁷, M⁺ is NH₄ ⁺, an alkali metal ion or 0.5 alkaline earth metal ion, R⁷ is a linear C₂-C₁₀-hydrocarbon radical substituted by at least one hydrophilic group and y and z, independently of one another, are each an integer from 0 to 50, and R⁵ is H if y is 0, and R⁶ is H if z is
 0. 2. A compound as claimed in claim 1, wherein R² is a polyisobutenyl having a number average molar mass of from 300 to 5000, preferably from 500 to 2300, particularly preferably from 500 to
 1000. 3. A compound as claimed in claim 1 or claim 2, where R⁵ and R⁶ are each C(O)R⁷, wherein R⁷ corresponds to the formula VI

where n is an integer from 1 to
 4. 4. A process for the preparation of a compound (I) as claimed in any of claims 1 to 3 by reacting dicarboxylic acids HO₂C—R¹—O₂H with amines R²—NH₂ and alkylene oxides of the formula III in a suitable sequence,

and, if required, by reacting the compound obtained in this manner with SO₃, P₄O₁₀ or compounds R⁷C(O)OH and, if required, then with NH₃ or alkali metal (alkaline earth metal) salts.
 5. A compound of the formula II

where R¹ is unsubstituted or C₁-C₁₂-alkyl-substituted C₁-C₈-alkylene or C₂- to C₈alkenylene, and R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₅₀-alkenyl.
 6. A compound of the formula IV

where R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₅₀-alkenyl, R³ and R⁴, independently of one another, are each H, methyl or ethyl and together contain not more than 2 carbon atoms, and R⁵ is H, M+, SO₃H, SO₃ ⁻M⁺, OPO₃H, OPO₃ ⁻M⁺ or C(O)R⁷, M⁺ is NH₄ ⁺, an alkali metal ion or 0.5 alkaline earth metal ion and R⁷ is a linear C₂-C₁₀-hydrocarbon radical substituted by at least one hydrophilic group.
 7. A compound of the formula V

where R¹ is unsubstituted C₁-C₁₂-alkyl-substituted C₁-C₈-alkylene or C₂-C₈alkenylene, R² is linear or branched C₈-C₃₅₀-alkyl or C₈-C₃₅₀-alkenyl, R³ and R⁴, independently of one another, are each H, methyl or ethyl and together contain not more than 2 carbon atoms, R⁵ and R⁶, independently of one another, are each H, M⁺, SO₃H, SO₃ ⁻M⁺, OPO₃H, OPO₃ ⁻M⁺ or C(O)R⁷, M⁺ is NH₄ ⁺, an alkali metal ion or 0.5 alkaline earth metal ion, and R⁷ is a linear C₂-C₁₀-hydrocarbon radical substituted by at least one hydrophilic group.
 8. The use of a compound as claimed in any of claims 1 to 3, preferably of a compound in which R⁵ and R⁶ are each H, as an emulsifier in the preparation of water-in-oil emulsions, the oil being a vegetable, animal or synthetic oil or fat.
 9. The use of a compound as claimed in any of claims 1 to 3, preferably of a compound in which R⁵ and R⁶ are not H, as an emulsifier of a fuel in the preparation of water-in-fuel emulsions.
 10. A water-in-fuel emulsion resulting from the use as claimed in claim 9 and containing from 60 to 95% by weight of fuel, preferably diesel fuel, from 3 to 35% by weight of water and from 0.2 to 10, preferably from 0.5 to 5, % by weight of a novel compound as claimed in any of claims 1 to 3, preferably of a compound in which R⁵ and R⁶ are not H, as an emulsifier.
 11. An emulsion as claimed in claim 10, wherein, in addition to the novel compound, one or more further emulsifiers, preferably sorbitan monooleate, C₁₃-oxo alcohol ethoxylates or alkylphenol ethoxylates, are present.
 12. A process for the preparation of an emulsion as claimed in claim 10 or 11, wherein the respective components are mixed with one another and are emulsified in a manner known per se, preferably in a mixing nozzle.
 13. The use of a compound as claimed in any of claims 1 to 3 as a surfactant, antiwear additive or lubricity-improving or corrosion-inhibiting additive in fuels, lubricants, fuel additive concentrates and lubricant additive concentrates or as a corrosion-inhibiting additive in aqueous liquids.
 14. A fuel, lubricant, fuel additive concentrate, lubricant additive concentrate or aqueous liquid resulting from the use as claimed in claim 13 and containing at least one compound as claimed in any of claims 1 to
 3. 